Patent GB-238626-A (GB)
Title: Improvements in or relating to brakes for vehicles
IPC: B60T8/26
Filed: 1924-05-24
Abstract: 238,626. Pugh, J. V., Barrington, T. B., and Rudge-Whitworth, Ltd. May 24, 1924. Force-transmitting mechanism. -In order that the maximum braking effect may be obtained the force applied to the brakes on the front and rear wheels respectively of a vehicle is automatically proportioned through a balance beam in accordance with the distribution of the load on the wheels taking into account the fact that the retardation of the vehicle produces a pitching or tilting couple which increases the load on the front wheels and diminishes that on the rear wheels. Fig. 1 shows a four-wheel braking arrangement for a vehicle in which the force applied to a pedal c is distributed by an equalizing or balance beam e to a pair of rockshafts a, b connected respectively by rods a<1>, a<2> and b<1>, b<2> to the brakes on the front and rear wheels. The rod c<3> extending from the pedal has a forked end d carrying a pin which is arranged to slide in a slot e<1> in the beam e against the action of springs e<2>, e<3>, Fig. 2. The forked end d is connected by a rod d<2> and bell-crank g<1> to a swing- ing weight g<3>. The position of the forked-end d with respect to the ends of the beam e is initially adjusted to correspond with the normal distribution of the load as between the front and rear wheels. When the brakes are applied, the weight g<3> swings forwardly by reason of the retardation of the vehicle and adjusts the position of the end d of the rod c<3> in the slot e<1> and thus the relative value of the force applied to the brakes on the front and rear wheels through the beam e, to correspond with the re-distribution of the load brought about by the action of the retarding force on the vehicle. The movement of the weight g<3> may be damped by the provision of friction washers at the pivot of the bell-crank g<1> or by connecting the end d of the rod c<3> to the piston of a dash-pot the cylinder of which is mounted on the beam e. In other arrangements the beam e is disposed longitudinally with respect to the vehicle and the weight is directly attached to the sliding end d of the rod c<3> or the end d is connected by a rod to a pendulum. As shown in Fig. 10, the beam e is vertically disposed and is provided with an inclined slot e<1>. When the brakes are applied the end d of the rod c<3> takes up a position in the slot e<1> against the action of a spring-plunger k arranged in the slot, such position and thus the distribution of pressure transmitted to the front and rear brakes being dependent upon the pressure applied to the pedal c. In a further arrangement, Fig. 12, the pressune applied to the pedal c is transmitted to the beam e through another balance beam l one arm of which is connected to the end d of the rod c<3> and thereby effects the adjustment of this end in relation to the beam e. The distribution of the braking force may be so arranged that the skidding pressure instead of being reached simultaneously on the wheels may be reached somewhat later on the front wheels as compared with the rear wheels. The invention may be applied to relay brake systems.